Fresh food articles are normally considered to be better raw material for preparation of food, than the corresponding frozen articles. This is especially true for fish and meat. Because of this, a large share of the fish industry is aimed at handling of cold stored fresh fish which is highly valued on the market. A contributory cause to the high prize, is that the fresh fod is sensitive and that unforseen delays in a transport chain may lead to loss of freshness and reduction in quality, so that the articles may not be approved for import or sale.
A more rational and efficient handling is possible with fish that has been taken, possibly gutted and immediately freezed to a temperature of about -38.degree. C., before entering "rigor mortis". This kind of fishing is being performed with large ships that may stay out for long util the cold-storage room has been loaded full. The forwarding of the frozen fish to retailers may be done without hast, as long as the freeze condition is maintained.
From the point of economics, the latter method has many advantages. However, problems often arise when thawing the fish, wherein the consistency and quality of the fish is lost. This has lead to a "bad reputation" for frozen fish. A lot of work has been put into improvement of thawing methods for frozen food articles, e.g. fish, but in reality, a method giving the desired results, i.e. putting freezed and thawed fish into full parity with high quality fresh fish has not yet been accomplished. For example, the recommendations for freezing/thawing of the Norwegian Board of Food stipulates that thawing of frozen fish may be performed in water or in water saturated air. If the fish is thawed in water, the water temperature should be between +14.degree. C. and +17.degree. C. If the fish is thawed in water saturated air, the air speed should exceed 5 m/sec. and have a temperature of between +14.degree. C. and +17.degree. C.